// 处理v-if
ifUpdater(node, key, value) {
    if (value) {
        node.style.display = 'block'
    } else {
        node.style.display = 'none'
    }
    new Watcher(this.vm, key, (newValue) => {
        node.style.display = newValue ? 'block' : 'none'
    })
}